Re: [PATCH v7 2/9] drm/bridge: Implement generic USB Type-C DP HPD bridge

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Thu, Oct 23, 2025 at 11:30:02AM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen@rock-chips.com>
> 
> Several USB-C controller drivers have already implemented the DP HPD
> bridge function provided by aux-hpd-bridge.c, but there are still
> some USB-C controller driver that have not yet implemented it.
> 
> This patch implements a generic DP HPD bridge based on aux-hpd-bridge.c,
> so that other USB-C controller drivers don't need to implement it again.
> 
> Signed-off-by: Chaoyi Chen <chaoyi.chen@rock-chips.com>
> ---
>  drivers/gpu/drm/bridge/Kconfig                | 11 ++++
>  drivers/gpu/drm/bridge/Makefile               |  1 +
>  .../gpu/drm/bridge/aux-hpd-typec-dp-bridge.c  | 51 +++++++++++++++++++
>  3 files changed, 63 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index b9e0ca85226a..9f31540d3ad8 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -33,6 +33,17 @@ config DRM_AUX_HPD_BRIDGE
>  menu "Display Interface Bridges"
>  	depends on DRM && DRM_BRIDGE
>  
> +config DRM_AUX_TYPEC_DP_HPD_BRIDGE
> +	tristate "TypeC DP HPD bridge"
> +	depends on DRM_BRIDGE && OF && TYPEC
> +	select DRM_AUX_HPD_BRIDGE
> +	help
> +	  Simple USB Type-C DP bridge that terminates the bridge chain and
> +	  provides HPD support.
> +
> +	  If the USB-C controller driver has not implemented this and you need
> +	  the DP HPD support, say "Y" or "m" here.

You don't need to depend on DRM_BRIDGE separately, but do you really
need a separate module for this in the first place?

>  config DRM_CHIPONE_ICN6211
>  	tristate "Chipone ICN6211 MIPI-DSI/RGB Converter bridge"
>  	depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 245e8a27e3fc..e91736829167 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_DRM_AUX_BRIDGE) += aux-bridge.o
>  obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) += aux-hpd-bridge.o
> +obj-$(CONFIG_DRM_AUX_TYPEC_DP_HPD_BRIDGE) += aux-hpd-typec-dp-bridge.o

Instead, why not just make that a part of aux-hpd-bridge
conditionally:

ifneq ($(CONFIG_TYPEC),)
        aux-hpd-bridge-y        += aux-hpd-typec-dp-bridge.o
endif


thanks,

-- 
heikki